Concrete-finishing apparatus

ABSTRACT

A concrete-finishing apparatus ( 10 ) comprises a relatively quickly rotating, powered roller ( 18 ) adapted to be moved relatively slowly across a bed, slab or layer of newly-laid concrete ( 11 ), while the latter is still fluid, with opposite ends ( 14, 15 ) of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller ( 18 ): a) containing internal stressing means ( 44 ) for applying longitudinal compression to the roller, between the ends ( 14, 15 ) of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed, and/or b) being adapted to be removed from the remainder of the apparatus ( 10 ) and dismantled, when not in use, into constituent, smaller, parts.

FIELD OF THE INVENTION

[0001] This invention relates to a concrete-finishing apparatus, thatis, apparatus comprising a relatively quickly rotating roller adapted tobe moved relatively slowly across a bed, slab or layer or newly-laidconcrete, while the latter is still fluid, in order to produce asmoothed surface thereon.

[0002] Prior Art

[0003] It is well established, indeed, it is conventional practice,after concrete has been laid to form a slab within confining “formwork”,and while the concrete is still fluid, for “striking-off”, or surfacefinishing, of the concrete, to be carried out.

[0004] Conventionally, striking-off has been achieved by means of awooden or metal beam, known as a “screed” or “strike-off template”,being pulled over the surface of the concrete, with the ends of the beamresting upon wooden or metal screed boards, the latter effectivelyforming part of the concrete-confining formwork, at opposite edges ofthe concrete.

[0005] It is now well established, however, instead of a beam, to use arotary roll tube, that is, a tubular roller, powered (i.e. rotated) byan air motor, hydraulic motor, electric motor or internal combustionengine, for the quick striking-off (i.e. surface-finishing) of newlylaid, still fluid, or still unset, concrete. The ends of the rolleroverhang, and rest upon, the formwork so that the roller is maintainedat the required level for the surface of the concrete. [Before concreteproperly “sets”, it becomes thixotropic, in which state it assumes astable, quasi-set condition, but can be fluidized by pokering, that is,mechanical working.]

[0006] Whichever implement is used, that is, a beam or roller, it has totraverse the full width of the concrete, and overhang the formwork, butshould not overhang the formwork excessively. That is to say, the lengthof the beam or roller has to be matched to the width of the concrete.Hence it has been necessary to stock a large range of lengths of beamsand rollers.

[0007] Long rollers are inconvenient to handle and to transport, and areliable to damage easily. Known tubular rollers tend to sag during use,producing an unwanted concave surface on the concrete. Known tubularrollers also are liable to becoming permanently bowed in storage or intransport, with the result that the concrete surface becomes wavy or atany rate uneven with the rotation of the roller.

[0008] Examples of relevant prior art include two United States PatentSpecifications, U.S. Pat. Nos. 4,142,815 (Mitchell) and 4,702,640(Allen)—U.S. Pat. No. 4,142,815 (MITCHELL) and U.S. Pat. No. 4,702,640(ALLEN). Reference is directed to both specifications. Slightly lessrelevant is a third United States Patent Specification, U.S. Pat. No.4,993,869 (Ulmer et al)—U.S. Pat. No. 4,993,869 (ULMER ET AL).

[0009] U.S. Pat. No. 4,142,815 (MITCHELL) discloses a concrete slabstriker which employs a counter-rotating roller to grade, or strike off,the concrete of a freshly poured concrete slab while the concrete isstill in the plastic state. Preferably the roller is formed from steeltubing, which may be filled with concrete for additional weight.

[0010] U.S. Pat. No. 4,702,640 (ALLEN) discloses a concrete finishercontrolled and driven by an end handle assembly including an internalcombustion engine for rotating a tubular roller.

[0011] U.S. Pat. No. 4,993,869 (ULMER ET AL) discloses a concretefinishing machine with vibrating finishing rollers.

[0012] None of these three specifications however addresses two problemswith which the present invention is concerned. One such problem is theabove-mentioned tendency of a concrete-finishing roller to sag, orbecome (permanently) bowed, due to its own weight, whereby the concreteis finished with an unintentionally non-flat surface. The other problemis that the roller(s) cannot be taken apart, or dissembled, either priorto use or subsequent to use.

SUMMARY OF THE INVENTION

[0013] In its broadest aspect the invention relates to a fluid finishingapparatus such as a concrete finishing apparatus or the like, comprisinga rotable, powered roller adapted to be moved over a surface of newlylaid fluid which is adapted to set, cure or otherwise solidify, with theroller surface in slipping contact with the fluid surface and withopposite ends of the roller maintained at the required level of thefluid surface, in order to produce a smooth finish to the surface of thefluid, said roller comprising means to maintain the roller at therequired level of the concrete surface along the entire length thereof,thereby to reduce the tendency of the roller to sag or becomepermanently bowed.

[0014] There are a number of different aspects to the invention.

[0015] According to a first aspect of the invention there is provided aconcrete-finishing apparatus comprising a relatively quickly rotating,powered roller adapted to be moved relatively slowly across a bed, slabor layer or newly-laid concrete, while the latter is still fluid, withopposite ends of the roller maintained at the required level of theconcrete surface, in order to produce a smoothed finish to the surfaceof the concrete, said roller containing internal stressing means forapplying longitudinal compression to the roller, between the ends of theroller, so as to reduce the tendency of the roller to sag or becomepermanently bowed. Suitably internal stressing serves to maintain theroller at the required level of the concrete surface, along the entirelength of the roller.

[0016] According to a second aspect of the invention there is provided aconcrete-finishing apparatus comprising a relatively quickly rotating,powered roller adapted to be moved relatively slowly across a bed, slabor layer or newly-laid concrete, while the latter is still fluid, withthe opposite ends of the roller maintained at the required level of theconcrete surface, in order to produce a smoothed finish to the surfaceof the concrete, said roller being adapted to be removed from theremainder of the apparatus and dismantled, when not in use, intoconstituent, smaller, parts.

[0017] Said constituent smaller parts may or may not remain looselyinter-connected after the dismantling.

[0018] According to a third aspect of the invention there is provided aconcrete-finishing apparatus comprising a relatively quickly rotating,powered roller adapted to be moved relatively slowly across a bed, slabor layer of newly-laid concrete, while the latter is still fluid, withopposite ends of the roller maintained at the required level of theconcrete surface, in order to produce a smoothed finish to the surfaceof the concrete, said roller:

[0019] a) containing internal stressing means for longitudinalcompression to the roller, between the ends of the roller, so as toreduce the tendency of the roller to sag or become permanently bowed;and

[0020] b) being adapted to be removed from the remainder of theapparatus and dismantled, when not in use, into constituent, smaller,parts.

[0021] Suitably internal stressing serves to maintain the roller at therequired level of the concrete surface, along the entire length of theroller.

[0022] Said constituent smaller parts may or may not remain looselyinter-connected after the dismantling.

[0023] The apparatus of the invention may serve as a fluid-finishingapparatus for any material which when newly laid is fluid and thereaftersets, cures or solidifies to form a desired product, in particularmaterials for construction of buildings, roads, foundations or likestructures in particular concrete, but also cement, tars or bitumens andthe like.

[0024] The roller of a concrete-finishing apparatus in accordance withthe first, second or third aspect of the invention is preferably adaptedto be driven, that is, rotated, by an engine or motor, either directlyor through a gearbox, at between 50 and 500, preferably between 100 and300, revolutions per minute (“rpm”) and the apparatus is preferablyadapted to be drawn over the concrete by means of two handles atopposite ends of the roller, and/or by means of a winch, or possibly twowinches, positioned at one end of the concrete. Reference herein to“relatively quickly rotating powered roller adapted to be movedrelatively slowly” is to the respective speeds of rotation, whereby theroller is caused to move and also causes the concrete surface to bedisplaced, i.e. a shear force is applied to the surface. It may bepossible to operate the apparatus optionally or alternatively in othermanner with respect to the relative speed of rotation and movement ofthe roller or the like in order to achieve a desired surface finishing.In use, the apparatus is preferably drawn across the concrete in theopposite direction to that in which the rotation of the roller istending to move the apparatus, i.e. such that the coincident surfaces ofthe roller and concrete serve to displace excess concrete towards thatpart of the concrete surface which has not yet been smoothed.Advantageously this provides a superior finish. Preferably the poweredroller is relatively quickly rotating in use, and is moved relativelyslowly across the surface of the concrete.

[0025] In the case of the preferred embodiments of the first and thirdaspects of the invention, that is, in the case where the roller containsinternal stressing means for applying longitudinal compression to theroller, between the ends of the roller, so as to reduce the tendency ofthe roller to sag or become permanently bowed, the internal stressingmeans preferably comprises one or more longitudinal tensioning members(preferably more than one) extending between and interconnecting twoend-plates, one at either end of the roller. The or each tensioningmember may comprise a cable, or a rigid rod, or a combination thereof.The rod may be wholly or partly screw-threaded for tightening thetensioning member so as to prestress the roller. A preferred form oftensioning member comprises a cable joined securely at opposite endsrespectively to two screw-threaded rods, each said rod being connectedto a respective one of the two end-plates. Preferably a single suchtensioning member is provided within the roller, extending axiallytherein. Preferably, a plurality, for example three or four of suchtensioning members are provided within the roller, equidistantly fromeach other and equidistantly from the axis of the roller. The cable maybe joined to each rod by a sleeve which is swaged onto the cable and isscrewed onto the rod. In the case of the preferred embodiment of thethird aspect of the invention, the longitudinal tensioning member may beremoved from the roller and dismantled into constituent smaller lengths,and may be reassembled with use of only some of its constituent lengths,or with use of all of said lengths together with additional lengths,whereby the length of the member may be adapted in convenient manner.Preferably the tensioning member comprises one or more rod sections atone or both ends and a single cable section therebetween or comprises asingle rod or cable section, each rod or cable section preferablyconstituting a constituent length.

[0026] In the case of the preferred embodiments of the second and thirdaspects of the invention, that is, in the case where the roller can beremoved from the remainder of the apparatus and dismantled, when not inuse, into constituent, smaller parts, the roller may be dismantled forthe purpose of reassembling with use of only some of its constituentparts, or with use of all of said parts together with additional parts,whereby the length of the roller may be adapted in convenient manner.The aforesaid smaller parts may comprise rigid cylindrical rollersections, with the axial ends of their cylindrical surfaces tightly heldtogether in axial end-to-end abutment. Additionally one or more of theaforesaid smaller parts may comprise dedicated end plates and/ordedicated coupling members, i.e. providing essentially end and/orcoupling portions, and substantially no roller surface portion.

[0027] The aforesaid member smaller parts may be of any number andindividual length as required to enable the construction of a roller ofdesired length, and to maintain the integrity thereof, preferably are of2 or more in number, for example 2 to 15, more preferably 2 to 10. Thesmaller parts are suitably of length enabling convenient transport andassembly acceptable lengthwise rigidity (i.e. so as not to sag or becomepermanently bowed), preferably are of length of 1 to 5 multiples of 0.3to 1.8 m, more preferably 1 to 5 multiples of 0.5 to 1.5 m for example 1to 5 multiples of the order of 1.0 m.

[0028] Preferably roller sections comprise an integral or removablecoupling portion at each end thereof, thereby enabling the coupling ofroller sections end-to-end. Such coupling portions may be like andadapted to couple with a dedicated coupling member, or may beeffectively male and female respectively and adapted to couple directlywith one coupling portion of another roller section. Preferably onecoupling portion of each roller section provides also an integral orremovable end plate, for example the male coupling portion provides anend handle, and an attachment means for the tensioning member, and adedicated end plate provides also a male coupling portion therebyenabling the assembly of a complete roller with use of any one or moreroller sections and a single dedicated end plate.

[0029] Preferably integral coupling portions/end plates comprise one ormore apertures therein to receive the tensioning member(s) along thelength of the roller. Preferably a single tensioning member passesthrough an aperture in the recess or projection of each female or malecoupling portion.

[0030] Either the surfaces themselves of the roller sections may formthe surface of the roller, or one or more sleeves may be fitted over theroller sections.

[0031] For example, a single sleeve may be fitted over all the rollersections. Alternatively a plurality of, i.e. several, sleeves may befitted over the roller sections. Sleeve ends may coincide with rollersection ends or, preferably, sleeve ends may be staggered axially inrelation to the roller ends, so that the sleeve ends are out of registrywith the roller section ends. Such sleeves may be formed from sheets,curved into cylindrical forms, the ends of the sheets being tucked intosurface slots, parallel to the roller axis, in the roller sections. Suchsleeves may be sacrificial, that is, designed to wear away in use and tobe replaceable.

[0032] According to a fourth aspect of the invention there is thereforeprovided a kit of parts for a roller as hereinbefore defined, comprisinga plurality of roller sections of different lengths and one or morededicated end plates. Preferably the kit comprises in addition atensioning member or its constituent parts, for example one (or more)cable section(s of different lengths) and a plurality of (pairs of) rodsections of different lengths, rod sections of any pair being of similarlength. Optionally the kit comprises a plurality of dedicated couplingmembers.

[0033] In a specific embodiment therefore the invention relates to anapparatus for use in striking-off or finishing newly laid, still fluid,concrete on site; said apparatus comprising a roller having acylindrical or nearly cylindrical outer surface which extends the wholelength, or substantially the whole length, of the roller, forstriking-off concrete; i.e. said apparatus being a powered strikerroller; each end of the roller being rotatably connected to a respectiveguidably moveable support of said powered striker roller; one or bothend(s) of the roller being formed as, or provided with, a (respective)shaft drivably coupling the roller to a motor or engine of said poweredstriker roller, for rotating the roller in use at a speed in the rangeof 50 revolutions per minute (“rpm”) to 500 rpm; each end of the rollerbeing directly or indirectly connected to a handle or the like, and/orto a winch or the like, for moving the roller over the concrete with thecylindrical or nearly cylindrical outer surface of the roller inslipping contact with the surface of the concrete; the roller beingcharacterised in that the roller is an assembly of constituent parts, atleast some of which are rigid and impart rigidity to the roller; in thatat least some of the constituent parts of the roller are in the form ofcylindrical or nearly cylindrical or part-cylindrical or part-nearlycylindrical members abutting closely together so as to leave no gaps oronly very small gaps between them so as to form or define saidcylindrical or nearly cylindrical outer surface of the roller; and inthat the roller can be partly or completely dissembled, before and/orafter use, into its constituent parts, for ease of transport to and/oraway from the site, and/or for replacement of a damaged part, and/or forvarying the effective span of the roller.

[0034] The rigid constituent parts of the apparatus may comprise aplurality of cylindrical or nearly cylindrical roller sections axiallyabutted together to form or define the cylindrical or nearly cylindricalouter surface of the roller. Each roller section is preferably tubular.

[0035] Preferably tensioning means extends throughout the interior orthe roller from one end to the other end of the roller, for applyingtension between the ends of the roller and thereby reducing a tendencyof the roller otherwise to sag, the tensioning means being adapted sothat the tension can be completely removed before or after use for theroller sections to be disconnected from each other.

[0036] The roller sections may be two or three or more in number, beingformed by two end sections or by two end sections and one or moreintermediate sections of the roller, each said ends section being formedwith, or provided with, respective bearings, comprising the two bearingswhereby the roller is supported or is adapted to be supported rotatablyby the machine.

[0037] The roller sections may inter-engage via unthreaded co-axialtaper portions, one male, one female, inter-engaging with each other.

[0038] One or more relatively thin cylindrical or nearly cylindricalsleeves may form said cylindrical or nearly cylindrical outer surface,and may be sacrificial and replaceable.

[0039] The constituent parts, or some of them, may be still looselyjoined together or may be completely separated from each other after thedissembly of the roller.

[0040] The invention will be further described, by way of example only,with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0041]FIG. 1 illustrates one form of apparatus embodying the inventionin use on a bed of fluid concrete;

[0042]FIG. 1A is an enlargement of a detail in FIG. 1;

[0043]FIG. 2 illustrates another form of apparatus embodying theinvention in use on a bed of fluid concrete;

[0044]FIG. 3 illustrates yet another form of apparatus embodying theinvention in use on a bed of fluid concrete;

[0045]FIGS. 3A, 3B, 3C and 3D are enlargements of details of FIG. 3;

[0046]FIG. 4 is a schematic side elevation of a three-section roller ofone apparatus embodying the invention;

[0047]FIG. 5 is a schematic side elevation of a longitudinal tensioningmember of stressing means shown in the embodiment of FIG. 1;

[0048]FIG. 6 is an enlarged end view of the stressing means;

[0049]FIG. 7 is a part-sectional view taken on line B-B in FIG. 6;

[0050]FIG. 8 is an enlarged view of an end-plate of the stressing means;

[0051] FIGS. 9-11 illustrate a sleeve on two roller sections;

[0052] FIGS. 12-14 illustrate oblique abutment surfaces;

[0053] FIGS. 15-17 illustrate castellated abutment surfaces;

[0054] FIGS. 18-22 show tapered male and female end portions provided onthe respective roller sections;

[0055] FIGS. 23-25 and FIGS. 26-28 respectively illustrate internal andexternal tubular bridging members;

[0056] FIGS. 29-34 show a roller covered by a removable sleeve;

[0057] FIGS. 35-37 illustrate two rods coupled together;

[0058] FIGS. 38-40 show part of a solid roller;

[0059] FIGS. 41-45 show male and female end-plates with mating conicallocating formations;

[0060] FIGS. 46-48 and FIGS. 49-54 show two variations on this;

[0061] FIGS. 55-56 show a one-piece stressed roller;

[0062]FIG. 57 shows a coupling;

[0063]FIGS. 58 and 59 show two forms of multi-section roller;

[0064]FIG. 60 shows another form of tensioning member;

[0065]FIG. 61 shows an unstressed, three-section, roller;

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS

[0066] Referring to the drawings, the apparatus 10 of FIG. 1 is adaptedto be drawn across a bed of still fluid concrete 11 by means of twohandles 12, 13 with the roller ends 14, 15 resting upon formwork 16, 17which the ends overhang. The roller 18 is powered by means of amains-powered electric motor 19.

[0067] The apparatus 20 of FIG. 2 is similar except for two winches 21,22 for drawing the apparatus over the concrete.

[0068]FIG. 3 illustrates a more robust apparatus 30 wherein the roller31 is rotatably mounted to two carriages 32, 33, one having aroller-powering motor 34. The formwork comprises two U-section beams 35,36 on their sides. The roller ends rest upon the tops of the beams 35,36 whilst the carriages 32, 33 have relatively small guide-rollers 37,38 which engage undersides or two top flanges of the beams 35, 36, so asto hold the roller 31 positively down, in contact with the formworkbeams 35, 36, this does away with the need for handles. The apparatus 30is drawn over the concrete by two winches 39, 40.

[0069] Referring now to FIG. 4, the strike-off roller or roll tube 41illustrated in FIG. 1 is, for example, 4 to 5 m long and 120 mm indiameter. It is in the form of an elongate hollow cylindrical body andconsists of two identical end sections 42, 42 and a middle section 43(which can be replaced by a shorter or longer middle section, notshown). The sections 42, 43, 42 are separably connected end-to-end asshown.

[0070] The roller 41 comprises stressing means 44 comprising 4 fourtensioning members 45, only one of which is shown, extending between twoend plates 46, 46. The tensioning members 45 are equally spaced from oneanother around the axis of the roller and are equally spaced from theaxis. The number of longitudinal tensioning members may be selecteddepending on the size of the roller. It is possible to use a singlelongitudinal tensioning member. However, there are preferably at leastthree. Each tensioning member 45 has two end nuts 47 engaging the endplates 46, 46 and tightened so as to put the tensioning member 45 intension, whereby the roller 41 is put under end-to-end compression andthereby resists sagging and/or becoming bowed. Each member 45 comprisestwo rods 48, 48 connected by a cable 49 whose length is selecteddepending on the length of the middle section 43; the cable 49 may bereplaced by a chain, rope, strand or wire, for example. Each end of thecable 49 is releasably connected to the associated rod 48 by a coupling50, which may comprise a sleeve swaged on the cable and screwed onto therod. The free end of each rod 48 has a screwthread engaged with nut 47which bears against the end plate 46 via an optional washer.

[0071] Tightening of the nuts 47 puts the longitudinal tensioningmembers 45 under tension and consequently puts the roller 41 underlongitudinal compression. This not only ensures that the sections 42,43, 42 are securely joined together but also stiffens the roller 41 inorder to resist bending. When a horizontal cylindrical body bends underits own weight, the uppermost generatrix shortens and the lowermostgeneratrix lengthens (elastic deformation). The stressing means 45applies compression to all of the generatrices thereby resistingextension of the lowermost generatrix and consequently resisting bendingof the body. For a roller 4 m long and 120 mm in diameter, the centraldeflection as measured by rolling the roller with its ends resting onparallel screed boards may be improved from 30 mm using a conventionalroll tube to a range round the circumference of 0 to 3 mm using a rolleras described above. Thus, it is possible to minimize the deflection on aparticular span or to achieve a longer span with a still acceptabledeflection. It is also possible to increase the diameter of the roller,using an increased number of longitudinal tensioning members 45.

[0072] A roller of a desired length may be made up from a kit of partsincluding end sections 42 and middle sections 43 of various lengths,from which the sections to be joined end-to-end are selected. Rods 48and cables 49 of suitable length are then selected accordingly, and theroll tube as shown in FIG. 4 is assembled. The roller is then supportedat its ends, and the central deflection (sagging) is measured. In orderto reduce this deflection to an acceptable level, the nuts 47 aretightened, preferably using a torque wrench to ensure that the tensionin the members 45 is approximately equal.

[0073] It is to be noted that the roller 41 may have a diameter whichdecreases slightly and gradually from the end regions toward a centralregion, to provide a negative camber. This is useful, for example, if asurface which rises towards the middle of the floor is to be formed whenthe roller is rolled over the concrete.

[0074] The strike-off roller may be driven in rotation by drive means(including a motor) at one end of the roller, or at each end of theroller if the span is particularly large.

[0075] The sections of the roller 41 may be made of metal (e.g. steel oraluminium), plastics material, or even wood, for example. Materials oflow density and high stiffness are preferred.

[0076] The elongate body may have, over at least the major part of itslength, a circumferential wearing surface which is replaceable. Thewearing surface may be constituted by a sleeve, which may be sectionaland/or flexible. A flexible sleeve, e.g. of plastics sheet or textilefabric, may be fitted on site, may be rolled up for easy transportation,and may extend over the full length of the roller.

[0077] For example, FIGS. 9-11 illustrate such a sleeve 51 on rollersections 52, 52.

[0078] Various modifications may be made within the scope of theinvention. For example, FIGS. 12-14 show an embodiment in which theabutment surface 53 a, 53 b on each section of the roller is a planarsurface oblique to the axis of the roller, e.g. at an angle of 30 to60°, preferably 45°. In FIGS. 15-17, the abutment surface again deviatesfrom a plane normal to the axis of the roller and constituted bycastellations 54 a, 54 b on the ends of the sections of the body. Bothof these embodiments provide a staggered joint which avoids forming anoticeable line on the surface of the concrete.

[0079] The embodiment shown in FIGS. 18-22 has tapered male and femaleend portions 55 a, 55 b provided on the respective roller sections.

[0080] In the embodiment shown in FIGS. 23-25 the two abutting ends ofthe sections 56, 57 are bridged by an internal stiffening member 58 inthe form of a tube, e.g. of rigid plastics material, of greater wallthickness than the tubular sections 56, 57.

[0081] In the embodiment of FIGS. 26-28, a relatively thin externaltubular bridging member 59 fits within reduced diameter end sections 60,61.

[0082] FIGS. 29-34 show a roller 62 covered by a removable sleeve 63serving as the wearing surface mentioned above and extending along thewhole length of the body. The ends 63 a, 63 b of sleeve 63 are fittedinto an undercut slot 64 in roller 62, parallel to the roller axis.

[0083] Two rods 65 a, 65 b may be coupled end-to-end by the coupling 66shown in FIGS. 35-37. Each rod 65 a, 65 b is cut away over more thanhalf its cross-section at the end and a transverse plate 67 a, 67 b iswelded to it. Each plate 67 is provided with a pair of holes 68 a, 68 boffset from the rod. The plates 67 are connected together by bolts 69passed through the holes 68, with the interposition of a washer, andretained by a nut 70.

[0084] FIGS. 38-40 show part of a solid roller body 71 whose sections72, 73 are joined by a threaded stub 74 on one section screwed into athreaded socket 75 in the other section. An optional removable sleeve76, as described above, is also shown.

[0085] FIGS. 41-45 show male and female end-plates 77, 78 with matingconical locating formations 79, 80. FIGS. 46-48 show a variation onthis.

[0086] FIGS. 49-54 show another variation, in which a double maleconical fitting 91 engages two female conical end-plates 92, 92 fittedrespectively to two roller sections.

[0087] FIGS. 55-56 show a one-piece stressed roller 93, containingstressing means as described and illustrated above.

[0088]FIG. 57 shows a coupling 94, the construction of which is clearfrom the drawing.

[0089]FIGS. 58 and 59 show two forms of multi-section rollers 95, 96.The roller sections in FIG. 58 have flat ends, whilst the rollersections in FIG. 59 have mating, non-flat ends.

[0090]FIG. 60 shows another form of tensioning member 97, theconstruction of which is as shown.

[0091]FIG. 61 shows an unstressed, four-section, roller 98, the sections98 a-98 d being coupled together by male and female coupling members 99,100.

[0092]FIG. 62 shows a roller section (101) having integral end plate(102) comprising an open ended cylindrical end handle (103) and atensioning member mounting (104), and having coupling portion (105)comprising an opening (106) adapted to receive a similar cylindricalhandle (103) of another roller section (101). The opening (106) andhandle (103) may be engaged by means of mating studs and apertures inthe respective supporting faces (102, 105) about opening (106) andhandle (103), and secured by means of the tensioning to be applied, ormay be engaged and secured by means of suitable threading on opening(106) and handle (103) or the supporting faces (102, 105).

[0093] A dedicated end portion is shown (107) having two end plates(103), one of which may associate with the coupling portion (106),thereby providing a complete roller.

[0094] A tensioning member (108) is provided along the axial length ofthe roller, via the open axis (109) thereof, suitably secured in placeby means of tensioning plates (110) and thereafter tensioned, or aboutthe axial length, via apertures (111) in similar manner.

[0095]FIG. 63 shows a kit of parts according to the fourth aspect of theinvention as hereinbefore defined, comprising roller sections (112) ofdifferent lengths, suitably 2×, 3× and 4× unit lengths, where the unitlength is dependent on the intended nature of the surface to befinished, suitably for concrete finishing, the unit length is 0.5-1.5 m,preferably 1 m or thereabouts. The sections (112) are shown each with anend plate (113) and a coupling member (114) (detail not shown). The kitalso includes a dedicated end portion (115), and optional dedicatedcoupling members (116).

[0096] A tensioning member (117) is shown in its component parts,comprising cable (118) of 2× unit length and pairs of rods (119) each of0.5×, 1×, 1,5×, 2×, 2.5× and 3.5× unit length, or 14 rods (120) each of0.5× unit length, or 7 rods (120) each of 1× unit length.

[0097] It will be apparent that a kit may comprise any component part ashereinbefore defined with respect to the description and figures, orcombination thereof.

1. A fluid finishing apparatus such as a concrete finishing apparatus orthe like, comprising a rotatable, powered roller adapted to be movedover a surface of newly laid fluid which is adapted to set, cure orotherwise solidify, with the roller surface in slipping contact with thefluid surface and with opposite ends of the roller maintained at therequired level of the fluid surface, in order to produce a smooth finishto the surface of the fluid, said roller comprising means to maintainthe roller at the required level of the concrete surface along theentire length thereof, thereby to reduce the tendency of the roller tosag or become permanently bowed, characterised in that the meanscomprise internal stressing means for applying longitudinal compressionto the roller, between the ends of the roller.
 2. A concrete-finishingapparatus according to claim 1, comprising a relatively quicklyrotating, powered roller adapted to be moved relatively slowly across abed, slab or layer of newly-laid concrete, while the latter is stillfluid, with opposite ends of the roller maintained at the required levelof the concrete surface, in order to produce a smoothed finish to thesurface of the concrete, said roller being adapted to be removed fromthe remainder of the apparatus and dismantled, when not in use, intoconstituent, smaller parts.
 3. A concrete-finishing apparatus as claimedin claims 1 or 2, wherein the internal stressing means preferablycomprises one or more longitudinal tensioning members each extendingbetween and interconnecting two end-plates, one at either end of theroller.
 4. A concrete-finishing apparatus as claimed in claim 3, whereinthe or each tensioning member comprises a cable, or a rigid rod, or acombination thereof.
 5. A concrete-finishing apparatus as claimed inclaim 4, wherein the rod is wholly or partly screw-threaded fortightening the tensioning member so as to prestress the roller.
 6. Aconcrete-finishing apparatus as claimed in any one of claims 3 to 5,wherein the tensioning member may be removed from the roller and bothmember and roller may be dismantled into respectively constituentsmaller lengths and parts and may be reassembled with use of only someof their constituent lengths and parts, or with use of all of saidlengths and parts together with additional lengths and parts, wherebythe length of the member and of the roller may be adapted in convenientmanner.
 7. A concrete-finishing apparatus as claimed in any one ofclaims 2 to 6, wherein the aforesaid smaller parts comprise rigidcylindrical roller sections, with the axial ends of their cylindricalsurfaces tightly held together in axial end-to-end abutment.
 8. Aconcrete-finishing apparatus as claimed in claim 7, wherein the surfacesthemselves form the surface of the roller, or wherein one or moresleeves are fitted over the roller sections.
 9. A concrete finishingapparatus as claimed in any of claims 2 to 8 wherein one or more of thesmaller parts may comprise dedicated end plates and/or dedicatedcoupling members, i.e. providing essentially end and/or couplingportions, and substantially no roller surface portion.
 10. A concretefinishing apparatus as claimed in any of claims 2 to 9 wherein thesmaller parts may be of any number and individual length as required toenable the construction of a roller of desired length and to maintainthe integrity thereof.
 11. A concrete finishing apparatus as claimed inany of claims 2 to 10 wherein the smaller parts comprise an integral ora removable coupling portion at each end thereof, which couplingportions are male and female respectively, the male coupling portionproviding an end handle, thereby enabling the assembly of a completeroller with use of any one or more roller sections and a singlededicated end plate.
 12. A concrete finishing apparatus as claimed inany one of claims 2 to 11, wherein the roller comprises a kit of partscomprising a plurality of roller sections of different lengths and oneor more dedicated end plates, in addition comprising an internaltensioning member or its constituent parts, in particular in additioncomprising a plurality of dedicated coupling members.
 13. A process forfluid, such as concrete, surface finishing comprising drawing theapparatus of claims 1-11 across the fluid in the opposite direction tothat in which the rotation of the roller is tending to move theapparatus.
 14. A process according to claim 13 wherein the roller issupported at its ends and the central deflection is measured, enablingdeflection to be reduced to an acceptable level by adjustment ofinternal stressing means.
 15. A process of assembly or dismantling anapparatus according to any of claims 1-12.